Different new access technologies and networks are being introduced towards mobile core networks and mobile services. Two examples of these are Generic Access Network (GAN), also known as Unlicensed Mobile Access (UMA), and Femto GSM and WCDMA solutions. The GAN solutions were initially defined in the 3rd generation partnership project (3GPP) TS 43.318 and 44.318 for 3GPP Releases 6 and 7. In these specifications, the GAN can be used to provide access to second generation public land mobile networks (PLMN) and the services available in these networks including GSM (Global System for Mobile Communication), EDGE (Enhanced Data rates for GSM Evolution) and GPRS (General Packet Radio Service networks). The interfaces used between GAN and the CN in these GAN solutions are the typical GSM RAN-CN interfaces, i.e. A and Gb interfaces for voice and data traffic, respectively, as defined in 3GPP TS 48.008 and 3GPP TS 48.018. In addition, work is now ongoing in 3GPP for Release 8 to specify generic access networks for third generation services, i.e. for UMTS (Universal Mobile Telecommunications System) or WCDMA (Wideband Code Division Multiple Access). The corresponding technical specifications will be called 3GPP TS 43.319 and 44.319 and will also include the previous content from specifications 43.318 and 44.318 in 3GPP Releases 6 and 7. This addition will provide the possibility to use the existing UMTS/WCDMA RAN-CN interfaces between the GAN and the CN, i.e. lu-cs and lu-ps interfaces, for voice and data traffic, respectively as defined in 3GPP TS 25.410. All these GAN solutions are based on usage of unlicensed radio technology and need new mobile terminals. Generic Access Network (GAN) is a technology that enables GSM and WCDMA services to be delivered over broadband access network and WLAN, at homes or in offices. End users will enjoy the same service as in the wide area network.
The Femto GSM and Femto WCDMA solutions use also, in a similar way as the GAN solutions, the existing RAN-CN interfaces, i.e. the A and Gb interfaces in the Femto GSM and the lu interfaces in the Femto WCDMA solution.
The GAN technology defines an access network to the mobile core network that can be used to access the existing circuit-switched and packet-switched services. The access network is based on use of unlicensed spectrum and IP-based broadband access networks that may include both wireless and wired portions. GAN can be seen as complementary to GSM and WCDMA radio networks providing local area coverage. The GAN infrastructure should preferably be integrated in to the existing radio network infrastructure to optimize network performance. With GAN the end user experience remains the same in the WLAN radio network as in GSM and WCDMA radio networks, including seamless handover and roaming between these radio networks. GSM and WCDMA services are available when the end user is connected via the WLAN.
The Femto GSM and WCDMA solutions are based on using existing mobile terminals and the existing licensed radio technologies.
The GAN solutions can be used in combination with an existing Access Point (AP), e.g. a WiFi or WLAN AP. The Femto GSM and Femto WCDMA solutions need a new Home Access Point (AP) to provide the local coverage at e.g. homes. Other call rates and other or additional services may be provided while the Home AP is used to access the mobile services. This means also that the operator macro GSM or WCDMA network is offloaded with the traffic created over the GAN or Femto solutions. The cheaper call rates are also needed as the end users pay and provide part of the communication needed (e.g. the Home AP and/or the broadband access connection).
The cheaper call rates for mobile originating calls and transactions are known and there exist different solutions for this need. Different charging for mobile terminated calls and other service differentiations when the new access technologies are used is also desired. A problem with service differentiation comes from the main advantage of the new access technologies, i.e. that the terminal has one single telephone number that is used when the terminal is connected via the existing macro networks and the new access networks. This means that the tariff or call rate can not be selected in the originating network only based on the called number of the B-party as the same number is used independently of the access network being used by the called party in the terminating network. In the same way, the transparency of the GAN and the Femto solutions to the CN (as existing RAN-CN interfaces are used) means that the CN in the terminating side is not necessarily aware of when GAN or the Femto solutions are being used by the called user.
There exists some IN (Intelligent Network) based solutions that can be used to have different charging based on “A” and “B” side locations, e.g. one tariff if both subscribers are in the same town. These methods are using information from the HLR, e.g. Location Number or VLR number. The main problem with such a solution is that one (MSC/)VLR cannot be used to serve different types of accesses (e.g. GAN, GSM, Femto GSM, Femto WCDMA) with different types of charging for mobile terminated calls. This problem comes from the fact that the HLR is for example not updated with a new VLR number when the end user moves between GAN and GSM accesses connected to the same MSC/VLR. In the same way, if “A” and “B” sides are connected to different networks, then the existing logic based on finding out that the users are in the same town using the same network can not be applied i.e. there is no known way to communicate the needed information between different networks and apply it for charging. One of the main goals with adding the new GAN and Femto solutions is to keep the added signaling load in the CN to a minimum possible. This means that it is desired that an end user moving between for example the GSM and GAN accesses doesn't need to change the current MSC/VLR. This means for example that Inter-MSC handovers and location updates are avoided to minimize the Inter-MSC and HLR signaling.